Valve mechanism for rock drills



y- 1934- w. A. SMITH, JR 1,965,264

VALVE MECHANISM FOR ROCK DRILLS Filed Aug. 121- 19:51

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Patented July 3, 1934 PATENT OFFICE VALVE MECHANISM FOR ROCK DRILLS William A. Smith, Jr., Phillipsburg, N. J., assignor to Ingersoll-Rand Company, Jersey City, N. J., a corporation of New Jersey Application August 12, 1931, Serial No. 556,561

7 Claims.

This invention relates to rock drills, but more particularly to a valve mechanism for rock drills of the fluid actuated type.

One object of the invention is to obtain a rapid 5 and efficient distribution of pressure fluid to the ends of the piston chamber for actuating the piston, and another object is to assure a powerful blow of the piston with a minimum charge of pressure fluid.

Other objects will be in part obvious and in part pointed out hereinafter.

In the accompanying drawing forming a part of this specification and in which similar reference characters refer to similar parts,

Figures 1 and 2 are sectional elevations of a rock drill equipped with valve mechanism constructed in accordance with the practice of the invention and illustrating the limiting positions of the distributing and reciprocatory elements of the drill.

Referring more particularly to the drawing, A designates generally a rock drill comprising a cylinder B having a piston chamber C therein for the accommodation of a reciprocatory hammer piston D. The piston chamber C is provided in this instance with a free exhaust port E which is controlled by a head F of the piston D.

A closure is provided for the front end of the piston chamber C in the form of a front cylinder washer G which extends into the front end of the cylinder B whereby it is centralized and has a bore H that serves as a guide for an extension or stem J of the piston D.

The washer G also serves to centralize the front head K with respect to the cylinder B and has an abutment for chuck mechanism designated generally by L and disposed within the front head K wherein it may rotate. The rear portion of the chuck mechanism L may be provided with suitable introverted ribs 0 to engage flutes P in the stem J in the usual manner so that the piston and the chuck mechanism will be slidably interlocked.

The chuck mechanism L, as is customary, serves as a guide for a hollow drill steel Q the rear or shank end of which is suitably exposed to receive the blows of the extension J of the piston D.

In the rear end of the cylinder B, that is, rearwardly of the piston chamber C, is an enlarged bore R for the reception of valve mechanism designated generally by S, rotation mechanism designated generally by T and a flange U of a back head V which serves as a closure for the extreme rear end of the cylinder B. The back head V which serves as a rearmost casing part of the drill may be secured to the cylinder B as may also be the front head K by the usual side bolts (not shown) but which may be arranged on diametrically opposite sides of the drill in the usual manner.

Apart from the function specified, the back head V also serves as a housing for a throttle valve W whereby the admission of pressure fluid into the drill may be controlled. The throttle valve W may, as indicated, be of the rotary type havinga central chamber X which may be in constant communication with a source of pressure fluid. In the wall of the throttle valve is a port Y adapted to register with a passage Z in the back head V and opening into a supply reservoir 1) of annular shape in the front end of the back head.

The rotation mechanism T comprises a rifle bar 0 which may be interlocked with the piston D in a well known manner. The rifle bar carries a head (1 wherein are arranged the usual spring pressed pawls e for engagement with the teeth 1 of a ratchet ring g encircling the head (1 and, in this instance, also serving as a seat for the flange U of the back head V.

The valve mechanism S, constructed in accordance with the practice of the invention, comprises a pair of plates it and j which form the valve chest. The plate 9' is disposed adjacent the rear end of the piston chamber C for which it forms a closure. The plate :1 is seated upon the plate It and acts as a seat for the ratchet ring y and the head d of the rifle bar.

The plates h and 7' are provided with central apertures k and 0 respectively to accommodate a bushing p disposed about the rifle bar 0 to form a bearing surface therefor and also to prevent unauthorized leakage of pressure fluid from the valve mechanism into the rear end of the piston chamber.

The opposing or adjacent surfaces of the plates handa' are suitably recessed to form a valve chamber 11 which consists of an outer annular groove portion r and an'inner shallow portion 5 which is of less length than the outer portion 1' wherewith it communicates along'its entire outer or peripheral extremity. Disposed in the outer portion 1 is a cylindrical valve 25 which controls the admission of pressure fluid into the valve chamber q.

On the outer surface and intermediate the ends of the valve is a flange u the rear and front ends of which constitute actuating surfaces 1) and w respectively. The flange it lies in an annular groove :0 encircling the outer portion 1' of the valve chamber, and from the rear end of the groove .10 leads a kicker passage y which extends through the cylinder B and opens into the piston chamber C at a point rearwardly of the exhaust ,port E. Similarly, from the front end of the groove a: leads a kicker passage 2 which opens into the piston chamber C at a point forwardly of the exhaust port E.

The pressure fluid controlled by the valve t and which flows from the supply reservoir b to the valve chamber through a supply pasage 2 flows over the rear and front ends of the valve t into the valve chamber. In passing over the ends of the valve the fluid exerts a holding pressure thereon so that, in effect, these ends constitute holding areas 3 and 4 respectively.

The supply passage 2 is in communication with the rear and front ends of the outer portion 7' of the valve chamber through branch passages 5 and 6 respectively. The passages 5 and 6 preferably open into the portion 1" at points slightly spaced from the extremities thereof so that the valve t will overrun the branch passages and thus prevent unauthorized admission of pressure fluid into the extremities of the portion 1'.

Disposed within the portions of the valve chamber q is a valve 7 of the reciprocatory plate type and having a central aperture 8 to receive the bushing p whereby said valve is guided. The valve '7 serves to control the admission of pressure fluid to the ends of the piston chamber C.

Such pressure fluid is conveyed to the rear end of the piston chamber by a rear inlet passage or passages 9 in the plate 7' and leading from the front end of the portion 3 to the rear end of the piston chamber. The admission of pressure fluid to the front end of the piston chamber is effected through a front inlet passage 10 in the cylinder B and the plate h and opening with its rear end into the rear end of the portion 8 of the valve chamber. Annular grooves 11 and 12 are formed in the front and rear ends of the portion 8 of the valve chamber q to assure an ample supply of pressure fluid to the inlet passages communicating therewith.

Preferably the outer annular portion r of the valve chamber q is of greater width than the portion of the valve t lying therein. Thus constructed, the end portions of the interior of the valve t may also serve as supply reservoirs into which pressure fluid may be admitted preparatory to the actuation of the valve '7. The valve 7, in the construction shown, extends somewhat beyond the confines of the portion s so that outer annular portions of the front and rear ends thereof may serve as actuating areas 13 and 14 respectively against which pressure fluid may act to assist in throwing the valve '7 from one limiting position to another.

On the front and rear ends of the valve 7 and concentrically with the areas 13 and 14 are other actuating areas 15 and 16. These are the portions of the end surfaces of the valve '7 which overlie the grooves 11 and 12 respectively and during the reciprocations of the hammer piston D the areas 15 and 16 will be exposed to compression flowing from the ends of the piston chamber C wherewith they are associated to assist in throwing the valve 7.

It is to be understood that sufficient clearance exists between the outer periphery of the valve '7 and the bore of the valve t to permit of free and independent movement of the valves without influencing each other. Such clearance should not be of an extent as to permit undue leakage of pressure fluid from one side of the valve 7 to the other.

The operation of the device is as follows: With the valves t and '7 and the piston D in the positions shown in Figure 1 pressure fluid will flow from the supply passage 2 across the holding surface 4 at the front end of the valve it into the valve chamber, thence through the portion s and the inlet passages 9 into the rear end of the piston chamber C. The pressure fluid thus admitted will drive the piston D forwardly against the working implement C.

As the piston D proceeds forwardly it will first uncover the kicker passage y to admit pressure fluid into the rear end of the groove 1:. Such pressure fluid will act against the actuating surface 1; and throw the valve t forwardly to close the branch passage 6 and uncover the branch passage 5 at the rear end of the portion 7' of the valve chamber. The valve 15 will thus out off the flow of pressure fluid to the rear end of the piston chamber and the piston will be thereafter urged forwardly in the direction of the working implement by the expansive force of the pressure fluid.

Shortly after the piston D uncovers the kicker passage 1/ the said piston will overrun the exhaust port E and the pressure fluid utilized for actuating the piston D forwardly will then escape to the atmosphere as will also that existing in the kicker passage y.

After the valve 73 has been thrown forwardly the rear actuating area 14 of the valve '7 will be exposed to pressure fluid tending to throw the valve 7 forwardly. The valve 7 will, however, remain seated in the rear extremity of the portion 5 of the valve chamber where it will be held by the pressure fluid acting against the entire front area of the valve.

Immediately prior to the time the piston D uncovers the exhaust port E the compression entrapped in the front end of the piston chamber C will flow through the front inlet passage 10 and into the groove 12 to act against the actuating area 16. As the piston proceeds forwardly, and in consequence of which the value of the compression in the front end of the piston chamber increases, the valve '7 will be thrown forwardly to uncover the groove 12. This movement of the valve 7 will occur simultaneously with the uncovering of the exhaust port E during the forward stroke of the piston D.

In the new position of the valves pressure fluid will flow from the supply passage 2 thrpugh the branch passage 5 over the rear holding surface 3 of the valve 15 and into the valve chamber. During its flow across the holding surface 3 such pressure fluid will act thereagainst to hold the valve t in its foremost limiting position. From the rear extremity of the portion 8 the pressure fluid will flow through the groove 12 and the front inlet passage 10 into the front end of the piston chamber C to return the piston D to its initial position.

During the rearward stroke of the piston, said piston will uncover the kicker passage 2. Pressure fluid will then flow into the front end of the groove x to act against the actuating surface w and will throw the valve t rearwardly thus cutting off the further flow of pressure fluid from the supply passage to the front end of the piston chamber and at the same time admitting pressure fluid to the front actuating area 13 of the Valve 7.

Upon continued rearward movement of the piston D the air compressed in the rear end of the piston chamber will flow through the inlet passages 9 and the groove 11 to act against the actuating area 15 of the valve 7. At the instant the piston D uncovers the exhaust port E the pressure fluid will be exhausted from the front end of the piston chamber and from the front end of the groove :1:. The valve t will, however, remain in its rearmost position where it will be held by the air acting against the holding area 4.

After the fluid is exhausted from the front end of the piston chamber C the compression acting against the area 15 and the live pressure fluid acting against the pressure area 13 will immediately throw the valve 7 rearwardly to its initial position. This movement of the valve 7 is efiected subsequently to the rearward movement of the valve 12. The piston D will thereafter be actuated rearwardly by the expansive force of the pressure fluid acting thereagainst throughout a period of time equalling that which. intervenes between the throwing of the valve t and the throwing of the valve 7. This delay in the movement of the valve 7 in following the valve 15, both in a forwardly and a rearwardly direction, may of-course be varied to suit immediate requirements.

In practice the present invention has been found to be extremely efficient. It not only assures a speedy action of the reciprocatory elements of the drill but has also been found to effect a very considerable economy in the consumption of pressure fluid in drills of this type.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a reciprocatory piston therein, a valve chamber comprising a pair of communicating portions, inlet passages leading from the valve chamber to the piston chamber, a pressure actuated valve in one portion of the valve chamber for controlling the admission of pressure fluid into the valve chamber, and a second valve in the other portion for controlling the admission of pressure fluid from the valve chamber tothe inlet passages and having actuating surfaces subjected to pressure fluid flowing directly thereto from the first said portion of the valve chamber.

2. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a reciprocatory piston therein, a valve chamber comprising a pair of communicating portions, inlet passages leading from the valve chamber to the piston chamber, a valve in one portion of the valve chamber actuated by pressure fluid valved by the piston for controlling the fiow of pressure fluid into the valve chamber, and a pressure actuated valve in the other portion for controlling the inlet passages and having actuating surfaces subjected to compression from the piston chamber and to pressure fluid flowing directly thereto from the first said portion of the valve chamber.

3. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a reciprocatory piston therein, a valve chamber in communication with the piston chamber and comprising a pair of communicating portions, an automatic valve in one portion to control the admission of pressure fluid into the valve chamber, a valve in the other portion to control the admission of pressure fluid from the valve chamber to both ends of the piston chamber, and actuating areas on the last mentioned valve subjected to pressure fluid flowing directly thereto from the first said portion of the valve chamber and to compression from the piston chamber for throwing the last said valve.

4. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a reciprocatory piston therein, a valve chamber in communication with the piston chamber, a valve to control the admission of pressure fluid into the valve chamber, actuating surfaces on the valve subjected to pressure fluid valved by the piston for throwing the valve, a second valve to control the admission of pressure fluid from the valve chamber to the piston chamber, opposed outer actuating surfaces thereon subjected to pressure fluid valved by the first said valve, and opposed inner actuating surfaces on the last said valve subjected to compression from the piston chamber to augment the pressure fluid acting against the outer actuating surfaces for throwing the said valve.

5. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a reciprocatory piston therein, a valve chamber in communication with the piston chamber and comprising a pair of concentric portions of different lengths, a valve in the portion of greater length to control the admission of pressure fluid into the valve chamber and having opposed actuating surfaces subjected to pressure fluid valved by the piston for throwing said valve, and a valve in the other portion of the valve chamber subjected to pressure fluid valved by the first said valve and to compression from the piston chamber for actuating the last said valve to control the admission of pressure fluid into the piston chamber.

6. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a reciprocatory piston therein, a valve chamber in communication with the piston chamber and comprising an outer annular portion and an inner portion of less length than the outer portion, a valve in the outer portion to control the admission of pressure fluid into the valve chamber and having opposed actuating surfaces subjected to pressure fluid valved by the piston for throwing the valve, a valve in the inner portion to control the admission of pressure fluid from the valve chamber into the piston, and actuating areas on the last said valve subjected to pressure fluid valved by the first said valve and tocompression from the piston to actuate the valve in the same direction as the first said valve and sequentially to the movement of the first said valve.

'7. In a fluid actuated rock drill, the combination of a cylinder having a piston chamber and a reciprocatory piston therein, a valve chamber in communication with the piston chamber and comprising an outer annular portion and an inner portion of less length than the outer portion, a valve in the outer portion to control the admission of pressure fluid into the valve chamber and having opposed actuating surfaces subjected to pressure fluid valved by the piston for throwing the valve, holding areas on the ends of the valve against which pressure fluid flowing into the valve chamber acts to hold said valve, a valve in the inner portion to control the admission of pressure fluid from the valve chamber into the piston, and actuating areas on the last said valve subjected to pressure fluid valved by the first said valve and to compression from the piston to actuate the valve in the same direction as the first said valve and sequentially to the movement of the first said valve.

WILLIAM A. SMITH, JR. 

